Kim Kardashian, Jennifer Aniston are getting the 'salmon sperm facial.' What is going on?

Is the secret to youthful, glowing skin found in salmon testicles? Kim Kardashian might be the person to ask.

On a recent episode of "The Kardashians," the reality television star, 43, told her mother Kris Jenner she got a "salmon sperm facial," while shooting promotional content for the Hulu series.

"I got a salmon sperm facial with salmon sperm injected into my face," Kardashian said, offering no further details.

She's not the only A-lister who's given this a facial a try either. Jennifer Aniston shared with The Wall Street Journal last year she also got a salmon sperm facial, though she wasn't sure it made a difference in her skin. “First of all, I said, ‘Are you serious? How do you get salmon’s sperm?’ ” Aniston said.

Known as "salmon pdrn," salmon testicle DNA has also been found in many luxury K-beauty products, including the KAHI Wrinkle Free Multi Balm, which has been popularized in TV shows like Netflix's "Extraordinary Attorney Woo" and in Doja Cat's "Vegas" music video. As the name implies, you glide the balm across your face for a dewy, luminous look.

Coating yourself with fish genital DNA may sound questionable, but beauty experts, along with an abundance of research, support its regenerative, anti-inflammatory effects. One study found that salmon sperm was associated with increased skin elasticity and stronger collagen levels – both of which are crucial for anti-aging skin.

"Having an open mind to these different types of ingredients can be really great. There are a lot of ingredients we're not used to in North America that are very popular in Korea, and there's a reason why: There's a lot of evidence behind its benefits," Kenna Whitnell, a biochemist and research scientist, previously told USA TODAY.

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What is salmon pdrn, and how does it work?

Salmon pdrn, which stands for "polydeoxyribonucleotides," is sperm DNA most commonly derived from salmon trout or chum salmon. Whitnell, who specializes in skincare consulting, said it works by targeting a specific protein that, when stimulated, promotes wound healing.

Some may wonder: Why the testicles? Whitnell said the genital area contains a high amount of DNA, making its extraction easier and more cost-efficient.

As for why salmon specifically, "the DNA of salmon is very close to that of humans, so it has a high compatibility with our own cellular functioning," Whitnell previously told USA TODAY. "The extraction and purification process removes active proteins and peptides that could potentially cause immune reactions. So it is just very purely DNA and that doesn't contain (anything) that could interact with our skin in a bad way."

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What are the skincare benefits of salmon testicle DNA?

Research has lauded salmon testicle DNA for its ability to restore skin elasticity, repair moisture barriers and reduce inflammation, making it a viable option for those with damaged or dry skin.

"This ingredient is great because if you have a cut, wound or acne blemish that is healing, salmon pdrn could help with that," medical esthetician Cassandra Bankson previously told USA TODAY about the process called "cell migration." "White blood cells will attempt to fix this wound … and (salmon pdrn) has been shown in research to help with that cell migration, or bringing the healing cells to that affected area."

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Who should avoid salmon sperm?

For most people, salmon pdrn is relatively safe with few known side effects. But those who are vegan or allergic to fish are advised to steer clear, and, despite its anti-inflammatory effects, it isn't meant to treat active acne, but rather dehydrated or wounded skin. 

"For salmon pdrn to work, it needs to get across the top layer of the skin, meaning the skin needs to be broken," Dr. Rachel Ho, an aesthetic doctor based in Singapore, previously told USA TODAY. Most studies, she added, have only tested salmon DNA's ability to repair skin that is damaged, rather than intact.

Because of the limited scope of available research, Ho suggested other evidence-based alternatives for repairing skin such as vitamin A, vitamin C or retinoids, which "can build collagen in the skin to treat early signs of aging or even hyperpigmentation." But before incorporating salmon sperm into your skincare regimen, experts advise patch testing any novel ingredient onto a small area of your skin to see how it reacts.

Contributing: Jenna Ryu, USA TODAY